Remote control system



May 19, 1936.

H. L. CARPENTER REMOTE CONTROL SYSTEM Filed Jan. ,25, 1928 6Sheets-Sheet 1 02.52 unison Mai NQ INVENTOR L. Carpenikr ATTORNEYS IWITNESSES v May 19, 1936. H. 1.. CARPENTER 2,041,393

REMOTE CONTROL SYSTEM Filed Jan. 25, 1928 6 Sheets-Sheet 2 POWER UNlT"LI-m. mmlllllulnl ll \VITNE SSES INVENTOR Hen-berb L.Car-pentcr' M BYW."

ATTORNEYS I y 1936. H. L. CARPENTER REMOTE CONTROL SYSTEM Fi led Jan.25, 1928 6 Sheets-Sheet 3 INVENTOR Jerbert L Carpenter ATI'OR NEYSWITNESSES- MAMA-J.

May 19, 1936. H. L. CARPENTER REMOTE CONTROL SYSTEM Filed Jan. 25, '19286 Sheets-Sheet 4 IN VENTOR Herbert L. Carpenter WITNESSES $6441 6'Vr-ATTORNEYS May 19, 1936.

H. L. CARPENTER O O O O O 0 000 o o o 0 WC n 06 0 El-IIW E o o 0 0 0I10! Remorz coumoa.

RADIO 5218: ncmors CONTROL OPERATING APPARATUS WITNESSES jag - 6Sheets-Sheet 5 LOUD SPEAK SPEAKER SPEAKERS AMPLIFYING APPARATUS AN 0REMOTE CONTROL APPIS.

VLNVENTOR I Herbert, Lhcarpent'en BY M ATTORNEY May 19, 1936.

H. L. CARPENTER REMOTE CONTROL SYSTEM Filed Jan. 25, 1923 6 Sheets-Sheet6 O O O o 00 o o 0 I543 INVENTOR WITNESSES Herbert L. Carpenw Y ATTORNEYPatented May 19, 1936 UNITED STATES PATENT OFFICE.

2 Claims.

This invention relates to remote control systems, and more particularlyto systems of that character for controlling the operation ofmulti-posit ion switches or rheostats. It is particularly adapted foruse in conjunction with the dials of radio reoeiving sets.

The invention further relates to the method of, and means for,controlling a system from a point remote therefrom. c

The invention contemplates a new remote control system and particularlya system of that character for controlling the operation of multipleposition switches, rheostats, condensers and other electrical andelectro mechanical devicesv requiring changing movement of theirposition and direction to perform their functions.

One object oi this invention is the control of the movement anddirection of movement of a multi-position switch, rheostat, dial, orsimilar device situated at one point, by a person located. at a pointdistant therefrom. I

Another object of this invention is the control of the multiple positionswitch, rheostat, condenser, loop-aerial or similarly operatable.device,

situated at one point and controlled by a person I at a point distanttherefrom.

at a point which may befdistant sound is being heard.

Another object is to provide means whereby the moving control elementsof a radioreceiving set or other sound producing or regulating apparatusmay be'located at some convenient point and may be operated at .willfrom one or more remote points with a relatively small and simple remotecontrol instrument with electromechanical indicators to indicate to theoperator at a remote point the position and condition of the variousoperating elements in the sound producing apparatus. i

Another object of this invention is to provide means whereby soundproducing apparatus may be operated from a remote point and controlledat, a point where the sound is being heard, 'without requiring themanual regulation of the apparatus in the usual control rooms or boardsor froml where the A further object of this invention is to provideelectromechanical means by which-sound producing apparatus and otherelectromechanical apparatus may be controlled and regulated more,sensitively than by manual regulation and movement of the controlmembers. 1

A further object of this invention is to make it possible to constructand build sound producing and receiving apparatus and otherelectromechanical apparatus in simple and inexpensive units of a sizeand arrangement oi parts, shielding, covers, etc., best suited toeconomic and proper operation and to locate such apparatus wheredesired, and to control its operation from a small, simple and portablecontrol instrument which can be made attractive and operated from a bed,chair, table or other convenient point, and where desired the portablecontrol instrument may be attachable at different places by suitablejacks. I

A further object resides in the providing of means whereby the presentmultiple tube sound producing or'recelving apparatus can be con.-structed very much cheaper than the present art provideswith'inexpensive cabinets for location in obscure places and yet providemeans to com- .pletely control such apparatus at various points at adistance from the apparatus with inexpensive portable controlinstruments, which indicate at any point applied the position andmovement 01' moving parts and whether the main apparatus, is inoperation from some other remote point or not.

Another object resides in the particular construction and arrangement ofparts and electrical circuits. which are hereinafter described andclaimed and shown in the accompanying drawings.

Another object of this invention is the method of controlling thequality and/or volume of one or more loud speakers.

Another object of this invention is the method I of controlling thequality and/or volume of a broadcastingstation, public address system,or

any other system of a similar character.

In accordance with this invention, one or more multi-position switchesor rheostats, located at point A, are connected over suitable indicatorcircuits to indicators at a distant point B, which indicators areadapted to vary their position or setting whenever the multi-positionswitches or rheostats with which they are associated change theirrespective settings. A suitable source of motive power is provided atpoint A, which is at point B. Whenever the desired setting 1% obtainedat point B the control circuits are opened and the multi-positionswitches at point A remain set until the operator at point B, desiringto change the setting at one or more of the multiposition switches,again closes the control circuits atgpoint B..

In the drawings comprising four sheets,-numbered Figures 1 to 13inclusive:

Figure 1 is a schematic of a control circuit and the control apparatusemployed in conjunction with a radio receiving set at point A.

Fig. 2 is a schematic drawing of the key circuits I and apparatusemployedin the control box at point B.

Fig.. 3 is a view in perspective of a suitable form of control box,wherein the apparatus shown in Fig. 2 may be assembled.

'Fig'. 4 is a plan view of the assembled apparatuszof 'Fig. 1,particularly showing the relays,

gears, and clutch mechanism employed in conjunction with the radio setat point A.

' is employed.

Fig. 8 is an enlarged cross section of one of the friction clutchmechanisms.

Fig. 9 is a view in perspective of a typical radio receiving set of thecharacter at present in use, including aloop aerial and a loud speaker,illustrating how applicant's control mechanism and remote control boxmay be combined therewith.

Fig. 10' is a detail view of an alternative form of clutch mechanism.Fig. 11 is a diagrammatic representation of the arrangement of theequipment of the remote control system.

Fig. 12 is a diagrammatic representation indicating how the remotecontrol system may be employed in an auditorium. I

' Fig. 13 illustrates another application of the j remote control systemused in conjunction with a 1 receiving set 900 is 'equippedwithdialsrepres'enting multi-position switches or rheostats ordinarily usedfor tuning purposes and for controlling the current in the filamentcircuits of a plurality of vacuum 'tubes of the character now--generally used for detecting and amplifying the received signals:.Ordinarily whenever the operator desires to tune the set the variousdials or multi-position switches are operated manually and the effectproduced is indicated in the loud speaker- 00L Frequently. however, theloud speaker is situated at a distance from the receiving set 000, andsometimes in a different room.

Likewise the loop aerial 002 is frequently situated at a point remotefrom both the receiving set 900 and the loud speaker L so that wheneverthe operator desires to vary the angle of the loop aerial 'or thestrength of the received signals or to tune out one station and tune inanother it is ,neoessarydor him to go to a distant point in the room orinto some other room in order to make the necessary changes.

In order to afford greater or from one point to another whenever achange in tuningis desired, a control box 000 may be manner.

flexibility of the apparatus, as well as to relieve the operator of thenecessity of moving from one room to another combined with the receivingset and situated adjacent thereto, which control box containsmechanismwhich is adapted to perform mechanically that which isordinarily performed by the-operator manually, that is, the control boxis adapted 5 to rotate the loud speaker, aerial and dials ormulti-position switches, back and forth at the will of the operator, whois thus enabled to observe the changed effect produced without movingfrom his chair. A suitable portable switch box ,903 is placed where itis accessible to the operator. This box contains indicators by meanswhereof the operator is enabled to observe the position of the dials ormulti-switches in the receiving set .900 and circuit closing switchesfor 15 controlling the machinery whereby said dials are operated.Suitable circuits are provided between the portable box 903 and theapparatus in the control box 904, which circuits are capable of beingopened or closed by the operator at will to 20 vary the setting of thevarious dials in the receiving set 900.

Referring to Fig. 1, the receiving set, as indicated within therectangle bounded by the dotted line, designated by the numeral I00, islocated at point A. It may include dials D-I and D-2, and rheostatsR--4,R-5' and R--B, as well as a, loop aerial of the general characterdisclosed at 902 in Fig. 9 The shafts of the dials D-I and D-2, areoperable to operate the tuning mecha- 30 nism, which may be of anypreferred form and the rheostats R-l and R5 are operable to control thevariable rheostats for varying the filament current of the vacuum tubes,in the usual The dials ordinarily used, such for example, as those shownin the receiving set 900, Fig. 9, are replaced by a series ofuniversally jointed shafts such as are shown inFig. 4, wherein joint I,Fig. 4, replace. dial D-I, Fig. 1, joint I22 replaces dial D2, joint M4dial R-4, joint 425 dial R5, and joint 426 dial R-S. Joint 423 isconnected by means of a shaft to the revoluble loop aerial LA, Fig. l.Mounted upon the respective shafts and rotating in unison therewith, arecontact fingers IOI, I02, I04, I05, I06 and I03, (Fig. l). Contactfingers I M and I02 pass over resistance coils, and fingers I04, I05 andI06 over arcuate metal strips.

Referring to Fig 4,120 represents the source of-motive power, in thepresent case an electric motor, geared by suitable gears to a drivingshaft 400. When the motor I20 is operated the shaft 400 is rotated andcauses the gears GM to 6055 inclusive, (Fig. 6) to rotate. Or if adriving shaft of the character disclosed in Fig. 7 is emplcggd thensaiddriving shaft would be roa Referring to Figs. 1 and 4, it-will be.observed. that a series of relays ,III- to IIG inclusive are provided,'which" are adapted; in one position to separate the-gears G2Iv to 626inclusive (Fig. 6) fromthe drivinggears'60l to 605 inclusive, and theirassociated inter-meshing gears ill to 6| 6' inclusive. In the otherposition the relays I II to 65 H6 inclusive, bring the gears I52I to 626into mesh with the gearsSI I to .GIS' inclusive. Thus whenever the motorI20 is in operation it is possible by operating one or more of therelays III to H6 inclusive, to bring one or more ofthe gears 62I to 626inclusive, into mesh with the rotating 7 gears 6 to BIS inclusive,whereby said gear (or gears) is caused to rotate, resulting in therotation in unison therewith of the corresponding shafts 4| I to 4 I sinclusive (Fig; 4) which produces 75 (Fig. 1) will be operated and acircuit will be a rotary movement of the corresponding multipositionswitch or rheostat.

' The principle of operation of the system is as follows:

The operator desiring to listen in upon the receiving set, inserts theplug of the control box (Fig. 2) into one of a series of multi-springjacks to which the cable I99 is wired. -It should be understood that thereceiving set may be equipped with a plurality of control boxes of thecharacter indicated in Figs. 2 and 3, each of these control boxesterminating in a multi-contact plugwhich is adapted to be inserted in asuitable multicontact jack (two of which are shown), which jacks arelocatedat different points as desired. If, when the plug of the controlbox is inserted in a jack, the station is in use, the busy relay I30closed to light the busy signal 201 as follows: From the positive sideof the A battery (Fig. 1) positive main battery feed to Fig. 2, leads269 and 2 I8, busy signal 201, leads 268 and I68, front con-' tact I32and armature I3I of relay I30, lead I 10 to the negative side of the Abattery. The busy signal 201, which we will assume is a miniatureelectric lamp, will be lighted over this circuit and the operator willthen be advised that the receiving set is already in use.

Assuming, however, that when the plug of the control box is inserted inthe jack the station is not in use, then the busy relay I30 will not beoperated and consequently the circuit for the busy signal will not beclosed at front contact I32 and armature I3I of busy relay I30. When theoperator fails to receive a positive signal upon the lamp 201 he willunderstand that thereceiving station is idle and will thereupon pressthe start key 2I1. Upon so doing, the busy relay will be operated overthe following circuit: From the 'ous switches.

positive side of the A battery (Fig. 1), Positive main battery feed,leads 269 and 2I8, contacts of start key 2I1, leads 261'and I61, windingof busy relay I30, negative main battery feed lead I10, to the negativeside of the A battery. Relay I30 operates over this circuit and connectsthe negative side of the A battery to the windings of the various relaysI4I to I46 (inclusive), to the winding of the motor start relay I22, tothe resistance coils associated with the contact fingers IOI, I02 andI03, and to the contact fingers I04, I05 and I06. The operation of relayI30 also causes the busy signal 201 to light over the circuit previouslydescribed. 7

It will be understood that any of the switches D--I, D-2, R-4, R5, R6and the loop aerial- LA may have been left in any position when thestation was last in use, and the operator may find it necessary todetermine the position of the vari- This is accomplished in thefollowing manner: Let us assume that we desire to determine the positionof the dial D-.-I. It will be observed that a resistance coil associatedwith erate as a voltameter and register the drop of potential acrossthat portion of the resistance coil between the negative side of the Abattery and the point where the contact member rests. The in- DI andD--2 and the position of the loop aerial c irdinarily it is unnecessaryto indicate the exact position of the rheostats controlling the filamentcurrent to the vacuum tubes in the manner heretofore described, it beingsufficient for the operator to note whether or not the rheostatscontrolling the filament current are normal or offnormal. Under thesecircumstances an indicator of the type of 2M may not be needed, it beingsufficient to substitute therefor a signal lamp of the character oflamps 204, 205 and 206 which are associated, as indicated in Fig. 1,with the rheostats R-4, Rr-5 and R6. When a lamp is used instead of avoltameter indicator, an arcuate contact is substituted for theresistance coil. In the normal operation ofthe rheostat the finger willbe in the position of contact finger I05 associated with the rheostatR-5 (Fig. 1) When the rheostat is in a position such that the filamentcurrent [has reached a critical value the contact finger tively, to oneside of each of the lamps 204, 205 V and 206, respectively, and that theother side of each of the lamps is connected by way of leads 2 I 5 and269 and the main battery feed to the positive side of theA battery. Thuswhenever the rheostat Rr-4 reaches the critical point the circuit forthe lamp 204 will\be closed at the contact finger I04, and the lamp 204will light as a warning or'danger signal to the operator. Simi-' larly,whenever the rheostats R5 and/0r R6 are at the critical point'thecircuits for lamps 205 and/or 206 will be closed at the contact fingersI05 and/or I06, as the case may be, with like effect.

Upon inserting the plug in the jack in the manner heretofore described,the operator may pick up a transmitting station forthwith, assuming thatthe receiving set is properly tuned for the reception of that station.Ordinarily, however,

the operator will find it necessary to tune the receiving station, inwhich case he will proceed as follows: It will be assumed that afterhaving observed the setting of indicator 20 I, the operator desires totune the dial D'I; in that event the key 2| I associated with theindicator 20I is closed to operate relay I II over thefollowing circuit:From the positive side of the A battery, leads 269 and 2I8, contacts ofkey 2 now closed, leads 266 and I66, winding of relay III, front contactI34 and armature I33, lead I10 to the negative side of the A battery.Relay I I I operated attracts its armature, which is of the pivotedlever type, thereby causing gear 62I (Fig. 6) to mesh with gear 6 I3.This operation is best understood from an examination of Figs. 5 and 6where it will be observed that, whenever relay II3 operates, gear 623meshes with'gear 6 I I.

The source of motive power for driving the gears shown in Figs. 4 to 7,inclusive, is a small electric motor I20. 'As the motor start key 225 isnot operated, however, motor I20 is disconnected and is consequently atrest. As soon, however, as key 2 is depressed, the operator determinesfrom observing the position of indicator 20I whether he desires torotate dial D-I clockwise or counterclockwise. If the dial is to berotated in a clockwise direction, that is, to the right, key 220 isoperated, let us, assume, to the right so that it makes contact withspring 222. A circuit is now closed to operate the motor start relay I22as follows: From the positive side of the A battery, leads 269 and 2I8,motor start key 220, contact spring 222, leads 25I and I5I, right-handwinding of motor start relay I22, front contact I34 and armature I33 tothe negative side of the A battery. The right-hand winding of motorstart relay I24 is energized and armature I23 is attracted so that itmakes contact with contacts I25 and I21. It should be understood thatthe motor start relay I22 may be of any preferred type but I prefer touse a three-position relay, that is, a relay where the armature has anormal position and left and right positions.

When the armature I23 is attracted to the right a circuit is completedto operate the motor as follows: From the power mains, lead I", armatureI23, right-hand contact I21, armature of motor I20, right-hand contactI25, field winding I2I, lead I12 to the power mains. The motor I20 nowcommences to revolve, revolving shaft 400 (Fig. 4), and gear 600 (Fig.6). Gear 600 drives the intermeshed gears 60I to 605, inclusive, and 6to GIS, inclusive. As the mesh gears rotate, gear 62I, which is in meshwith gear 6I3, will be rotated in unison therewith, thereby causingshaft 4 to rotate and vary the position of the device controlled by thedial D-I, which we will assume to be a tuning condenser. As the dialD--I rotates in a clockwise direction, the contact finger IOI willrotate in unison therewith, and the indicator 20I will vary its settinglikewise in a clockwise direction. If the direction of rotation iscontinued, the contact finger associated with therheostat- IOI willultimately reach the extreme position, and at that time the indicator20I will b e deflected to a maximum.

Let us assume, however, that the operator now desires to rotate the dialD-l in a counter-clockwise direction, that is, to the left. He willaccordingly hold key 2I I depressed and at the same time move the motorstart key 220 from the right-hand position to the left-hand position,thereby opening at contact 222, the circuit heretofore described. At themoment that the circuit was opened at the contact 222, of the motorstart key, armature I23 of the motor start relay was released, openingthe circuit of the motor I20, which immediately ceased running. Thisresulted in stopping the intermeshed gears which in turn resulted in thestoppage of gear 62I controlled by relay IIII When the motor start key220 is placed in the left-hand position, it closes the following circuitat contact 22I: From the positive side of the A battery, leads 269 and2I8, contacts 220 and 22 I of the motor start key, leads 250 and I50,left-hand winding of the motor start relay I22, front contact I34 andarmature I33 to the negative side of the A battery. The left handwinding of the motor start relay I22 is now energized, and armature I23is attracted to the left, closing contacts I24 and I26 to complete thefollowing circuit for the motor: From the power mains, "lead "I,armature I23, contact I26, armature of motor I20, contact I24, field I2Iof the motor, lead I12 to the power mains. It

will be observed that the motor I20 is now connected in the reversedirection and consequently rotates in the reverse direction with theresult that the gear 62I is rotated in a counter-clockwise direction.The contact finger IOI rotates in unison with the gear 62I and the shaft4I I, all in a counter-clockwise direction. The indicator 20I followsthe setting of the contact finger IN and decreases its deflection in acounter-clockwise direction, that is in the direction of zero.

If the operator desires to vary the position of the dial D2, theprocedure heretofore described for varying the dial D-I is followed,except that insteadof depressing key 2, key 2I2 is depressed, closing acircuit over leads 265 and I65 to operate relay H2. The operation ofrelay II2 causes shaft I42 to bring gear 622 into mesh with gear 6I4.The direction of rotation of gear 622 and, consequently, of dial D--2and the associated contact finger I02 will be clockwise orcounter-clockwise depending upon the right or left position of the motorstart key 220. Any variation in setting of the contact finger I02 withrespect to its associated resistance will cause the indicator 202 tovary its setting. The circuit for indicator 202 is controlled over leadsI54, 254 and 255, I55.

Similarly, to vary the position of the loop aerial LA, the motor startkey 220 is turned either to the right or the left position and key 2I3is operated in conjunction therewith. Operating the latter key closes acircuit over the leads 264 and I64 to operate relay II3. Relay II3operated causes gear 623 to mesh with gear 6, thereby causing the loopaerial to rotate and the posi-' tion of the contact finger I03 to vary.The angle of deflection of the loop aerial is indicated upon indicator203 which is controlled over a circuit including leads I56, 256 and 251and I51.

The rheostats R4 and R-5 are controlled in a similar manner, the circuitfor controlling rheostat R4 including key 2I4 and relay H4; and thecircuit for controlling rheostat R-5 including key,,2l5 and relay H5.The operation of relay II4 causes gear 624 to mesh with gear 6I2, whilethe operation of relay II5 causes gear 625 to mesh with gear 6I5. In thenormal operative position of rheostats R-4 and R,5, the

contact fingers I04 and I05-do not make contact with their associatedarcuate metal segments. As soon, however, as the rheostat reaches thecritical point as heretofore described, the contact finger I04 or I05,as the case may be, makes contact with its associated metal segment,thereby extending the negative side of the A battery over leads I58 and258 to lamp R-4 or over leads I59 and 259 to lamp R-5, thereby lightingthe lamp. 1

In some instances, R 6 may be a rheostat control, as indicated at I00 inFig. 1, but in the present case it will be assumed that R-G is intendedto control the loud speaker or power unit as indicated in Fig. 4. In anyevent, the rheostat or power unit at R-6 is controlled by the operationof key 2I6 which operates relay II6 over leads 26I and NH. Relay II6operated causes gear 626 to mesh with gear 6I6 and the direction ofmovement will depend upon the position of the motor start key 220.Contact finger I06 operates in the same manner as contact fingers I04and I05 and controls the positive or negative signal displayed by lamp206.

If, for any reason, the gear mechanism becomes clogged or locked, afterthe dials have reached the extreme position, no injury will be the shaft400 is rotated, the friction disk 800 is rotated in unison therewith.The surface of the disk 800 isipressed by spring 802 against, and makesgoodafriction contact with, the surface of the disk "80L sleeve gear 600so that when disk 80l is rotated, main gear 600, which controls themovement of all the gears of Fig. 6, rotates in unison there- 'with.Whenever the load upon the gear 600 becomes excessive, however, the disk000 carried by the shaft 400 will continue to rotate so long as motorI20 is rotated, but the disk 80I will remain stationary, therebypreventing any of the 'gearsfrom stripping or any of the associatedmechanism from-being injured.

Fig. 10 illustrates another form of clutch mechanism which may beemployed if preferred in place of the clutch mechanism illustrated inFigs. 4, 5 and 6 heretofore described.

The mechanism of Fig. 10 consists of an electromagnet I000 having anarmature I 00I pivoted at I002 to a suitable standard I001. Rotatablysecured to the opposite end of the armature mm is a pinion I008. Securedto the driving shaft I006 is a gear I003 rotatable in unison with theshaft. The shaft I005 which it is desired to drive is furnished with agear I004. In the po-.

thence through the pinion I 008 and gear I004 to the shaft I005, therebyvarying the position of the switch. When the switchhas reached thedesired position, relay I000 will be de-ener'gized causing its armatureIO0I to be released where-;

by the pinion I008 will disengage with the gears I003 and I004 and theshaft I005 will cease its' rotary movement.

Referring to Fig. 11, the receiving set 00 equipped with the loop aerialIIOI may be placed in any desired position. The unit H00 will consist ofthe radio receiving set and remote control apparatus in combination andfrom the unit a'cable H02 will be ca'rried'to any desired pointin anyroom selected where it will be terminated in jacks H03 and H04. Jack 03is pro- 1 paratus in the unit II00, as well as the position vided totake care of the connections for the control box I I05, which may besimilar in .all respects to control-box of Fig. 2. Jack II04 is providedto take care of the connections for the loud speaker H06. Jacks H03 andII04 are multiplied in various rooms, as indicated in Fig.

ers H06 areflalso connected to the circuit. With the apparatus in thecondition illustrated in Fig. 11 it would be possible for an operator ateither control box I 05 to control the operation of the radio receivingset and the remote control apof the loop aerial I IOI, therebyreproducing the Disk I is'locked at 804 to theordinary way hasthespeaker .or microphone I202 connected by means of a suitable cableI204 to the control apparatus I200 which may be situated. either in theauditorium or at some point adjacent thereto. The remote controlapparatus I200 is likewise connected by means of a suitable cable I206to a bank of loud speakers I203 situated either in the auditorium orexternal thereto. The remote control box I20I is like-- wise connectedby means of a suitable cable I201 to the control apparatus I200. Theoperator having custody of the remote control'unit I2 0I may be seatedat'some point in'the auditorium where he is in a position to listen, tothe speech broadcasted by the loud speakers I203. When- 2 ever theoperator desires to increase the volume or quality of the speech, all heneeds to do is ,to depress the key controlling the output either of themicrophone I202 or of the loudspeakers I203 or any or all of them as thecase may be, and to observe the 'result of the variation thus producedin the volume and quality of the broadcasting by the loud speakers I203.A unit of this character in the custody and control of acapable operatorwill obviate many of the difiiculties heretofore inherent in thebroadcasting of speeches by means of a public address system.

Fig. 13 illustrates another application of the invention to the controlof a broadcasting station. The. microphones I300 to I304 inclusive, 4are intended to be placed at various points in the studio or at variouspoints in an orchestra for the purpose of picking up the subject matterwhich it is intended to broadcast. The rheostats I3I0 to I3I4 inclusive,are intended to control theflow of current in each of the microphones I300 to I304 inclusive, respectively. 0 0

As will be observed, the microphone circuits are connected to a suitableamplifier and oscillator unit indicated in. blank at I330 where the 5undulating currents set up by the speech waves in the severalmicrophones are amplified and broadcasted by means of the aerial I33I. Areceiving station is provided consisting of the or- 5 dinaryconventional receiving set including an aerial I342, a control box I343and a loud speaker I344 andthe operator having the custody and controlof the control box I3 is able to listen to the I. program actuallybroadcasted from the 6 broadcasting station. It will be understood thatthe receiving unit indicated in the lower portion of Fig. 13 may besituated either adjacent to the broadcasting station or at a pointremote therefrom. All that is necessary is that the con- 6 trol box l34lshallbe connected by a suitable cable I340 from the-receiving station tothe remote control operating apparatus I3I5 controlling the microphonesI300 to I304 inclusive. 0

In operation the system functions as follows: n The orchestra or theactors proceed to perform their act at the studio and the variousmicrophones I300 to I304 inclusive pick up the musicor voice and'thecurrents thus produced are amplified and broadcasted bv the aerial I33Iof the 7 ceiving station listens in upon his receiving set consisting ofthe aerial I342, unit I343 and loud speaker l3 and is enabled to observethe quality and volume of the music 'thus detected. If the quality orvolume, is not satisfactory,- the operator merely depresses the keycontrolling one or more of the microphones I300 to I304inclusive,'thereby causing the apparatus in the con trol box I5 at thebroadcasting station to be energized to varythe position of. one or moreof the variable resistances I3I0 to I3 inclusive. The operator isenabled to observe the eflect of the manipulation of the switches andwhen the desired quality or volume has been obtained the key or keys ofthe control box I 3 which has been depressed are released and therheostat controlsof the variable resistances I3I0 to I 3 inclusive againcome to the position of rest. .The principal advantage of a system orthe character set forth in Fig. 13 is that the operator knows that he ispicking up the program as actually broadc'asted and that if the qualityand volume at his receiving set is satisfactory the quality and volumein other receiving sets similarly si tuated will also be satisfactory.

While for purposes of illustration, the control box I3 is connected by acable l340'to the control apparatus Ill! which is indicated as adaptedto control the current output of the micro-g phones, it should beunderstood that the control box I3 might also be connected by a suitable8 cable to the controls for the amplifier and osequally applicable toany system wherein it is desired to operate an electrically-operateddevice to produce an eifect for the amusement or edification of anaudience while at the same time providing a control device adapted to beoperated by some person who, being positioned among, and forming a partof, the audience, whereby he is enabled 'to observe the efiect producedas normally received by other members of the audience, is thereby in aposition to control the operation of the electrically-operated device tovary the eflfect produced, while simultaneously observing the characterof the changes as fast as the same are produced.

What is claimed is; I 1. In a radio remote control system, a receivingstation having a plurality of movable members, a pluraiity of remotecontrol stations, means for connecting any of said control stations withsaid receiving station, means cooperating with the first means formoving any of said movable members at said receiving station from any ofsaid remote control stations, and indicating means at ,each controlstation operated in response to the operation of the second means atanother station for indicating the position of the movable member beingcontrolled.

2. In a radio control system, a receiving station having a plurality ofmovable members, remote control station's, indicators at each ofsaidcontrolstations, circuitsfor controlling the movable members and theindicators, means connected in said circuits for electrically connectingany one of said control stations with said receiving station to thuscause an indicator at each control station to move in response to theadjustment of the selected movable member to indicate the position ofthe latter.

HERBERT L. CARPENTER.

